Touch Sensitive System and Method for Cognitive and Behavioral Testing and Evaluation

ABSTRACT

Portable operatively simple touch screen apparatus uses testing methods and systems that are free of age and language constraints include special signal processing techniques that provide a temporal resolution highly sensitive for probing cognitive function. The embodiments include or make use of one or more modules implemented at least partially in a set of instructions in software and configured to measure user reaction times to visual stimulus on a touch screen device having a capacitive sensor touch-sensitive surface and a detector of audio waves resulting from touch on the touch-sensitive surface. The modules employ recordation of acoustic vibrations resulting from a user&#39;s touching a target location on the touch screen surface spaced from a touched starting location on that surface, in one embodiment, to measure temporal response to a visual stimulus placed at the target location.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims under 35 U.S.C. § 119(e) the benefit of U.S.Provisional Application 61/772,474 filed on Mar. 4, 2013, the content ofwhich is incorporated in its entirety.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

The present invention was developed in part with funds from the NationalScience Foundation Grant 0924636. The United States Government hascertain rights to the invention.

TECHNICAL FIELD

This disclosure relates generally to the field of medical informatics.More specifically, the disclosure relates to the computerizeddetermination, evaluation or testing of diagnostically relevant data, inparticular, for assessing the normality of cognitive or executivefunction of the human brain.

BACKGROUND

Reaction times (RT), also called response times, and error rates (ER) onsimple behavioral tasks have been shown to be valuable diagnostic toolsfor assessing the normality of cognitive or executive function of thehuman brain. Response time measures the amount of time it takes for aperson to make a decision and effect a response following thepresentation of a stimulus, and is a very common measure in experimentalpsychology to examine sensation, perception, cognitive, and motorfunction.

Cognitive dysfunction can arise with varying severity. Two commonly usedclinical techniques are adequate to evaluate cognitive function inmoderate to severe cases: brain imaging (functional magnetic resonanceimaging, positron emission tomography, magnetoencephalography, orelectroencephalography) and neuropsychological testing.Neuropsychological and imaging tests are generally not sensitive todetect subtle cognitive deficits. Neuroimaging methods are the leastsensitive of all and are useful for predicting cognitive functionalchanges only if brain injury is moderate to severe. There are otherproblems beyond lack of sensitivity in neuropsychological and imagingtechniques. The brain imaging technique is not portable, requiresexpertise to administer, and is slow to produce results. It is also verycostly and is unsuitable for repeated use as would be needed forlongitudinal monitoring. Neuropsychological testing also takes arelatively long time, requires expertise to administer and evaluate, andis very sensitive to language related issues. Some neuropsychologicaltests are unsuitable for repeated testing because of practice effects,learning, and strategies. These shortcomings negatively impact the easeof administration and interpretation and field applicability of thesetechniques.

Another clinical technique for measuring cognitive and executivefunctions in humans is eye movements. Eye movements have demonstratedbrain areas important for processing visual stimuli and generatingstimulus driven eye movement responses. Eye tracking devices track eyemovements such as a saccade, which is a brain initiated quicksimultaneous movement of both eyes in the same direction. Prosaccade eyemovements involve a reflexive motor movement directly to a target. Anantisaccade task is a voluntary eye movement task that involvesinhibition of the reflexive movement towards the target and generationof a voluntary or goal directed movement of the eyes in the oppositedirection of the target location²⁰⁻²² (the superscripts refer topublications listed by numerical sequence in the “Publications” part ofwritten description immediately preceding the Claims). An antisaccadetest can be used to determine deficits in executive functioning.¹⁶⁻¹⁹Several studies have demonstrated that eye tracking tasks are moresensitive than standard neuropsychological testing in detectingdifferences in cognitive or executive function¹²⁻¹⁴. For example,publication number 12 ((Hill S K, Reilly J L, Harris M S, Khine T,Sweeney J A (2008) Oculomotor and neuropsychological effects ofantipsychotic treatment for schizophrenia. Schizophr Bull 34:494-506))showed that eye tracking (or oculomotor) biomarkers were more sensitiveto treatment-related changes in neurocognitive function than traditionalneuropsychological measures.

Detecting mild cognitive dysfunction is extremely important because manyof these mild problems if not detected early can lead to serious andsometimes fatal long-term outcomes. It is thought that less violent headimpacts that are repeated in a short interval can be more damaging. Thisproblem has reached national attention in the sport of professionalfootball where subtle brain injuries have resulted in long term effectson memory and emotional functions and have raised awareness in a muchgreater population of people who participate in youth sports withpotential for head impacts. Early detection of mild cognitivedysfunction is also very important for men and women in our armed forcesas well as for emergency rooms throughout the country due to car orbicycle accidents and falls. Being able to track small changes incognitive function will allow us to determine the most effectiveguidelines, interventions, and treatments. Cognitive deficits occur inmany human brain disorders including psychiatric (e.g., schizophrenia),developmental {e.g., attention deficit hyperactivity disorder), andneurological {e.g., Huntington's disease). Detecting subtle differencesin cognitive deficits is important for diagnosis or distinguishingsubtypes that require different treatments or to identify theintervention, treatment or drug with optimal cognitive outcome. Thusearly detection of mild cognitive dysfunction may also help withdiagnosis, evaluation and discovery of treatments.

As mentioned, eye-tracking devices are able to detect subtle cognitivedeficits with good temporal resolution for precise measurement ofbehavioral response times. Unfortunately, these devices are six figureexpensive, time intensive, cumbersome, cause physical discomfort(wearing device(s) on the head, lengthy physical restraint of headrequiring long motionless periods for accurate assessment), useelaborate and complicated machinery requiring complicated environmentalcontrol, require constant calibration and maintenance, necessitatetraining and expertise by someone with technical expertise to beaccurate in administering the test, and require substantial dataanalysis.

There is therefore a great need for an inexpensive (thus potentiallyeasily and widely available), portable and field operable, simple tooperate device not needing constant calibration and maintenance forquick detection and monitoring of cognitive dysfunction, especially mildor subtle cognitive dysfunction, that can be used on school orprofessional sports sideline or locker room examinations, or in doctorsoffices or outpatient care, or in battlefield emergency care or otherplaces in the field, or for low cost educational uses for health careprofessionals.

Recently, portable computing devices have become available that combinea display and a touch sensitive surface, allowing the user to interactwith the display using touch with their own fingertips. However, intheir current state, touch sensitive devices do not have touch temporalresolution sufficient to meet the need for in the field quick, accurateand precise detection and monitoring of cognitive dysfunction,especially mild or subtle cognitive dysfunction.

BRIEF SUMMARY OF THE INVENTION

Embodiments are disclosed that provide portable, field-convenient,potentially widely-available, simple to operate apparatus using methodsand systems that are free of age and language constraints yet are highlysensitive for probing cognitive function. The embodiments include atouch sensitive device with special signal processing techniques thatprovide a temporal resolution comparable to expensive eye tracking dataacquisition systems. The embodiments include or make use of one or moremodules implemented at least partially in a set of instructions insoftware and configured to measure user reaction times to visualstimulus on a touch screen device having a capacitive sensortouch-sensitive surface and a detector of audio waves resulting fromtouch on the touch-sensitive surface. The modules employ recordation ofacoustic vibrations resulting from a user's touching a target locationon the touch screen surface spaced from a touched starting location onthat surface to measure temporal response to a visual stimulus placed atthe target location.

The embodiments provide a quick process (method) of assessingsensory-motor and executive function in a subject to measure and/ortrack sensory-motor and cognitive changes due to impact to the head,thereby to enable treatment or intervention. Tests can be completed onsite at a speed of four to eight minutes in present embodiments. Theutility of such a portable and user friendly diagnostic device incontexts such as youth or professional bodily impact sports or in combatzones or in emergency rooms or doctors offices, or for clinicalneurophysiological determination and tracking of brain degeneration dueto disease or ageing, and/or developmental changes, has implications forrapid and universally accessible screening and diagnostic tools forbrain injuries.

This Summary is provided to introduce a selection of concepts in asimplified form that are further described below in the DetailedDescription. This Summary is not intended to identify key features oressential features of the claimed subject matter, nor is it intended tobe used as an aid in determining the scope of the claimed subjectmatter.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic of an embodiment displaying two tasks on atouchscreen of a tablet computer for testing cognitive function in anembodiment of the invention.

FIG. 2 is a schematic displaying finger touches on a touchscreen of anembodiment for a Pro-Point task and an Anti-Point Task for testingcognitive function.

FIG. 3 is a schematic displaying finger touches on a touchscreen deviceof an embodiment for an Anti-Point Task for testing cognitive function,wherein touch of the target destination creates acoustical vibrationsthat are sensed by an internal microphone of the device.

FIG. 4 is a chart of audio, visual and touch event and log timer timesof the events in the methods and systems of FIGS. 5A and 5B.

FIG. 5A is a block diagram of a method and system according to anembodiment of the invention for measuring and recording user touch taskreaction times on a touchscreen device in a test for cognitive function.

FIG. 5B is a block diagram of a method and system according to anembodiment of the invention for using data collected according to themethod and system of FIG. 5A and correcting the data recorded by thetouch screen device obtain accurate and precise reaction times in a testfor cognitive function.

FIG. 6 is a block diagram of a method and system according to anembodiment of the invention for measuring and recording user touch taskreaction times on a touchscreen device in a test for cognitive functionfor recording actual reaction times using a device created sound.

FIG. 7 is a chart of audio, visual and touch event and log timer timesof the events in the methods and systems of FIG. 6.

FIG. 8 is estimated mean initiation, movement, and total reaction timesfor soccer and non-soccer subjects as explained in a test ofembodiments.

DETAILED DESCRIPTION OF THE INVENTION General Preliminary Comments onEmbodiments and Terminology

The invention and the various features and advantageous details thereofare explained more fully with reference to the nonlimiting embodimentsthat are illustrated in the accompanying drawings and detailed in thefollowing description. Descriptions of well known starting materials,processing techniques, components and equipment are omitted so as not tounnecessarily obscure the invention in detail. It should be understood,however, that the detailed description and the specific examples, whileindicating preferred embodiments of the invention, are given by way ofillustration only and not by way of limitation. Various substitutions,modifications, additions and/or rearrangements within the spirit and/orscope of the underlying inventive concept will become apparent to thoseskilled in the art from this disclosure. Embodiments discussed hereincan be implemented in suitable computer-executable instructions that mayreside on a computer readable medium (e.g., a hard drive, flash drive),hardware circuitry or the like, or any combination.

The embodiments make use of a touch screen device having atouch-sensitive surface. The touchscreen device may be configured in avariety of ways. For example, the touchscreen device may be configuredas part of a mobile communication device such as a mobile phone, atablet computer, as part of a traditional computing device (e.g., adisplay device that is part of a laptop or personal computer), and soon. The touchscreen of the touchscreen device is configured to detectcontact when being touched with a finger of a user's hand with thetouchscreen using touch sensors. Examples of such touch sensors includecapacitive touch sensors. In a projected capacitance an X-Y grid may beformed across the touchscreen using near optically transparentconductors (e.g., indium tin oxide) to detect contact at different X-Ylocations on the touchscreen. Other capacitance techniques are alsocontemplated, such as surface capacitance, mutual capacitance,self-capacitance, and so on.

Generally, any of the functions described herein can be implementedusing software, firmware, hardware (e.g., fixed logic circuitry), or acombination of these implementations. For example, the touchscreendevice may be implemented using a computing device. The computing devicemay also include an entity (e.g., software) that causes hardware of thecomputing device to perform operations, e.g., processors, functionalblocks, a “system-on-a-chip,” and so on. The program code can be storedin one or more computer readable memory devices. The term “module” asused herein generally represents software, firmware, hardware, or acombination thereof.

At least portions of the functionalities or processes described hereincan be implemented in suitable computer-executable instructions. Thecomputer-executable instructions may be stored as software codecomponents or modules on one or more computer readable media. In oneembodiment, the computer-executable instructions may include lines ofcomplied C++, Java, HTML, or any other programming or scripting code. Inthe case of a software implementation, the module represents programcode that performs specified tasks when executed on a processor.

A “processor” (e.g., CPU or CPUs) includes any hardware system,mechanism or component that processes data, signals or otherinformation. A processor can include a system with a general-purposecentral processing unit, multiple processing units, dedicated circuitryfor achieving functionality, or other systems. Processing need not belimited to a geographic location, or have temporal limitations. Forexample, a processor can perform its functions in “real-time,”“offline,” in a “batch mode,” etc. Portions of processing can beperformed at different times and at different locations, by different(or the same) processing systems.

The features of the techniques described below are platform-independent,meaning that the techniques may be implemented on a variety ofcommercial computing platforms having a variety of processors.

The computing device may include a computer-readable medium that may beconfigured to maintain instructions that cause the computing device, andmore particularly hardware of the computing device to performoperations. Thus, the instructions function to configure the hardware toperform the operations and in this way result in transformation of thehardware to perform functions. The instructions may be provided by thecomputer-readable medium to the computing device through a variety ofdifferent configurations. A “computer-readable medium” may be any mediumthat can contain, store, communicate, propagate, or transport data or aprogram for use by or in connection with an instruction executionsystem, apparatus, system or device. The computer readable medium canbe, by way of example, but not by limitation, an electronic, magnetic,optical, electromagnetic, infrared, or semiconductor system, apparatus,system, device, propagation medium, or computer memory. Suchcomputer-readable medium shall generally be machine-readable and includesoftware programming or code that can be human readable (e.g., sourcecode) or machine-readable (e.g., object code). One such configuration ofa computer-readable medium is a signal-bearing medium configured totransmit the instructions (e.g., as a carrier wave) to the hardware ofthe computing device, such as via a network. The computer-readablemedium may also be configured as a computer-readable storage medium andthus is not a signal bearing medium. Examples of a computer-readablestorage medium include a random-access memory (RAM), read-only memory(ROM), an optical disc, flash memory, hard disk memory, and other memorydevices that may use magnetic, optical, and other techniques to storecomputer-executable instructions and other data executable by the CPU.But within this disclosure, the term “computer-readable medium” is notlimited to ROM, RAM, and HD and can include any type of data storagemedium that can be read by a processor.

An embodiment can include one or more computers network. In anembodiment, the computer has access to at least one database over thenetwork.

Additionally, the functions of the disclosed embodiments may beimplemented on one computer or shared/distributed among two or morecomputers communicatively coupled in, to or across a network.Communications between computers implementing embodiments can beaccomplished using any electronic, optical, radio frequency signals, orother suitable methods and tools of communication in compliance withknown network protocols.

Any examples or illustrations given herein are not to be regarded in anyway as restrictions on, limits to, or express definitions of, any termor terms with which they are utilized. Instead, these examples orillustrations are to be regarded as being described with respect to oneparticular embodiment and as illustrative only. Those of ordinary skillin the art will appreciate that any term or terms with which theseexamples or illustrations are utilized will encompass other embodimentsthat may or may not be given therewith or elsewhere in the specificationand all such embodiments are intended to be included within the scope ofthat term or terms. Language designating such nonlimiting examples andillustrations includes, but is not limited to: “for example,” “forinstance,” “e.g.,” “in an embodiment.”

As used herein, the terms “comprises,” “comprising,” “includes,”“including,” “has,” “having” or any other variation thereof, areintended to cover a non-exclusive inclusion. For example, a process,process, article, or apparatus that comprises a list of elements is notnecessarily limited to only those elements but may include otherelements not expressly listed or inherent to such process, process,article, or apparatus. Further, unless expressly stated to the contrary,“or” refers to an inclusive or and not to an exclusive or. That is,unless otherwise indicated, the term “or” is generally intended to mean“and/or”. For example, a condition A or B is satisfied by any one of thefollowing: A is true (or present) and B is false (or not present), A isfalse (or not present) and B is true (or present), and both A and B aretrue (or present).

As used herein, a term preceded by “a” or “an” (and “the” whenantecedent basis is “a” or “an”) includes both singular and plural ofsuch term (unless in context the reference “a” or “an” clearly indicatesonly the singular or only the plural).

As used in the description herein, the meaning of “in” includes “in” and“on” unless the context clearly dictates otherwise.

Description of Embodiments

Our objective was to develop a variant of the well-establishedantisaccade task for testing frontal-lobe executive function but insteadof using traditional eye tracking apparatus we wanted a device designedto be portable and field operable, potentially easily and widelyaccessible, free of language and age constraints, simple to use, buthighly sensitive for probing cognitive functions.

To address the need for portability and field operability, we chose atouch sensitive tablet device for testing. The initial development wasconducted on an Android™ operating system tablet having a touch screeninterface. However, for better consistency with other lab hardwareplatforms, the final prototype of one embodiment was developed for anApple iPad® touch screen tablet computer. (All references herein to aniPad tablet in development work, and in the field-testing in theExamples, are to the first generation iPad unless specific reference ismade to the successor model “iPad2.”)

We then addressed the need for very high sensitivity of probingcognitive functions using a touch screen portable tablet computer.Without highly sensitive tests, it would be impossible to measure mildcognitive changes (either deficits or enhancements, for example withinterventions). We developed a simple iPad-based application based on avariant of the well-established antisaccade task for testingfrontal-lobe executive function. We wanted the testing to be as simpleas possible and administered with minimal language and age requirements.Point responses by the hand towards a target are similar to prosaccadeeye movements in that they both involve a more reflexive motor movementdirectly to a target; while point responses away from a target are moresimilar to antisaccade movements as they also involve inhibition of thereflexive movement towards the target and generation of a voluntary orgoal directed motor movement in the opposite direction of the targetlocation²⁰⁻²². Point responses by the hand towards a target herein arecalled “Pro-Point.” Point responses away from a target herein are called“Anti-Point.” We designed the application to implement complementaryPro-Point and Anti-Point tests.

Referring to FIG. 1, panel A shows a touch screen tablet device 1 with atouch sensitive surface 2 in which a first fixed location 3 is generatedby the application (here, a central dot) and a plurality of additionalfixed locations 4 a, 4 b, 4 c, 4 d are generated (here square frames)equally radially spaced from first location 3 on touch sensitive surface2. At least one of the additional locations 4 a, 4 b, 4 c, 4 d isopposite another one of the additional locations 4 a, 4 b, 4 c, 4 d. Forexample, location 3 b is location opposite 3 d. All additional locations4 a, 4 b, 4 c, 4 d are equally circumferentially spaced from a nextcircumferentially adjacent additional location. For example, location 4b is next circumferentially adjacent additional location 4 a.

Panel A of FIG. 1 shows a Pro-Point task with a white arrow 5 (not partof the application) indicating a direction of a correct response, whichis toward the target square 3 b where a visual stimulus (whiteillumination) has been generated by the application.

Panel B of FIG. 2 shows an Anti-Point task with white arrow 6 indicatingdirection of a correct response (away from the target square 3 b where avisual stimulus light has been generated).

The iPad touch screen generates capacitance signals on touching that arecaptured to record Pro-Point and Anti-Point touch responses.

Referring to FIG. 2, in the application we developed, at the beginningof a test trial the touch screen on a tablet computer displays a dot atthe center of the screen and displays four white frames surroundingcenter dot (see FIG. 2, top). The test subject puts his/her finger onthe central dot and holds it there. After a delay, a white squareappears randomly in one of the four white frames surrounding the dot(white square location chosen randomly). The subject is instructed totouch the location at which the white square appears as soon aspossible. The pro-point test consists of 48 trials administered in twoblocks of 24 trials. A set of a minimum of 48 correct Pro-Point trialsare rapidly repeated. If the wrong square is touched or if there is toolong a delay is responding to the visual stimulus of the flashed whitesquare, a trial error is recorded and added to the 48 correct trials.This is the Pro-Point test. It serves as a control for generalalertness, sensorimotor function, and stimulus driven brain functions.Various trial specific items are recorded on each trial, including thetime elapsed between the display of the white square and the exactlocation where the finger first landed.

The Anti-Point test (FIG. 1, bottom) is identical to the first test inall aspects except one: in this test, the subject is instructed to touchthe location opposite to where the white square appeared as soon aspossible. Additional time needed for the second task reflects additionalcognitive processes (inhibition of stimulus driven responses and willfulgeneration of a response). Further, any changes (with respect to anindividual's baseline for repeated testing or with respect to anothercontrol population) that might only occur in the performance in thesecond test (but not the first test) can be attributed to changes incognitive functions.

The foregoing procedures are embodied in a set of instructions for acomputing device as depicted in the block diagrams of FIGS. 5A.Referring to 5A, data is collected. At 100, a program of instructions isstarted for a tablet computer 1 having a touch screen 2 (reference FIG.1). At 102, the program directs the tablet computer 1 to start recordingaudio vibrations to an audio file in a computer readable medium of thetouch screen device and to write timer time to a log file (Ta) on acomputer readable medium. At 104 the user being tested starts a trial bytouching the center (center 3 of FIG. 1) of the screen 2. At 106, theprogram directs the tablet computer 1 to draw (light) a target on one ofthe squares 4 a, 4 b, 4 c or 4 d of the touch screen 2 and write a timertime to a log file signifying the time the target is drawn (Tv). At 108,the user touches a target (either the drawn lighted square in aPro-Point trial or a square opposite the lighted square in an Anti-Pointtrial). At 110 the computer microphone 7 picks up vibrations created bythe user's touch of target and writes a timer time to a log filesignifying the time the touch vibrations are sensed by microphone 7(Tt). At 112, the computer receives notification of touch from the touchscreen of the computer and the location coordinates of the touch andwrites a timer time to a log file signifying the time the notificationis received (Tc) and write the location of touch to file. A set of anumber of error free trials (48 in the examples described herein) isconducted at 114 by instruction to return to 104 and start anothertrial, until the full set is completed, as at 116, at which time, at118, the computer is instructed to close the audio and log files onto acomputer readable medium which may be in the computer or incommunication with the computer, whereupon at 120, the program ofinstructions is ended.

The foregoing comprises a system and method of measuring user reactiontimes to visual stimulus on a portable touch screen device having acapacitive touch-sensitive surface, an acoustic sensor proximal thesurface, and one or more modules implemented partially in software, themodules being responsive to a user start command to a) open a time logfile on receipt of the start command; b) coincident with step a),commence recording for input signals from the acoustic sensor to anaudio file and write a timer time to a log file signifying the time ofthe start of this monitoring (Ta); c) generate a visual stimulus at afirst location on the touch screen surface for touch by a user; d)generate at least one second visual stimulus at a second location on thetouch screen surface spaced from the first location and write time ofgeneration of the second visual stimulus to a log file signifying suchtime of generation (Tv); e) receive notification of capacitance sensedtouch and coordinates of such sensed touch and write timer time to a logfile (Tc) signifying time of such sensed touch and also write the sensedtouch coordinates location to a file; f) remove the second visualstimulus from the touch screen surface, steps c)-f) comprising a singletrial; and g) repeat steps c)-f) until a set of trials signified by apredetermined number of capacitance sensed touches (Tc) of the secondlocation attains a preset number, then cease repeating steps c)-f), andclose the audio and log files onto a computer readable medium which maybe in the computer or in communication with the computer.

The Pro-Point and Anti-Point embodiments of the foregoing system andmethod are ones in which step b) further comprises generating a firstfixed location and a plurality of additional fixed second locationsequally radially spaced from the first location on the touch sensitivesurface, at least one such additional second location being oppositeanother such additional location and any additional second locationsbeing equally circumferentially spaced from a next circumferentiallyadjacent additional second location, and step d) further comprisesgenerating at least one second visual stimulus on one of the additionalsecond locations on the touch sensitive surface.

Correctness of timing of the recordation of events in our measurementsystem comprising a developed Pro-Point and Anti-Point test using atouchscreen device is critical to detection of mild or subtle cognitiveimpairment. Essentially our measurement system is a timing device. Itmeasures time of response to visual stimulus. The purpose of the systemis to get timing values that are as close as the system permits to trueor real world values and to do this repeatedly. The accuracy of ameasurement system is the degree of closeness of measurements of aquantity to that quantity's actual (true) value. The precision of ameasurement system, related to reproducibility and repeatability, is thedegree to which repeated measurements under unchanged conditions showthe same results. Correctness requires accuracy and precision.

It is well known that touchscreen devices are slow to detect that theyare being touched. Modern touchscreen devices internally use acapacitive touch sensitive mechanism that does not have the hightemporal resolution necessary for precise measurement of behavioralresponse time. Typically, current capacitive touch-based devices arepolled at 60 Hz and are able to report a change in touch status (e.g.contact) every 50 or so milliseconds, even when screen refresh rates andprocessors are super fast and optimal.

In order to examine the correctness of timing of various events in thesystem (e.g. when the visual stimulus at a square 4 a, 4 b, 4 c, or 4 dis turned on and when the finger touches a designated location inreaction to that stimulus), we examined the timing externally, i.e.,independently of the iPad's internal capacitance touch signaling systemand recording system. Referring to FIG. 2 the test subject is showntouching the center dot. A light trigger in a covered corner location ofthe tablet device was programmed to flash the exact time a target waspresented on a stimulus square. A photodiode aligned with the locationof the light trigger reacted to the light trigger and generated a pulsecaptured and recorded by an oscilloscope to capture the exact time thestimulus appeared on the screen. Still referring to FIG. 2, the subjectlifts off the center spot and touches the square opposite the presentedtarget. In order to determine if the finger's landing time is registeredprecisely, a piezo acoustic transducer sensor was used. A piezo acoustictransducer sensor detects vibrations. The moment that the finger landson the iPad again, the piezo sensor produces an electrical signal thatis captured by oscilloscope 32 and recorded. Conventional analog todigital processing circuitry was employed to convert analog electricalsignals to digital signals that were recorded.

A 5 mW red laser module can be used to illuminate a photodiode placed onthe opposite side of an iPad. The photodiode detects light coming from alaser. Referring to FIG. 2, as long as the finger is still touching theiPad, light from laser does not reach the photodiode. One can measurethe moment a finger is lifted to move to a target, because laser lightreaches laser light receiving photodiode and the exact time of theelectrical signal arising from photodiode can be captured and recorded.This test can be used to calibrate use of a detection of audiovibrations caused when a finger is lifted from the center spot as asignal for start of the timing of movement from center spot to apresented target or opposite a presented target.

This external capture of the time elapsed between onset of visual targetand when touch is sensed was compared to the time elapsed between onsetof visual target (“Tv”, as further explained below) and when touch issensed and internally registered on the iPad itself (“Tc”, as furtherexplained below). We found that the elapsed time for when the target wasdetected touched by the native iPad capacitance scheme (iPad latencies)was significantly slower than when touch was recognized by externalmeans (real-world touch latencies). We also did additional control teststo verify that the slower times were not due to a delay in the internalregistration of the visual onset but specifically in the internalrecognition and registration of touch. The native touch screen eventsdid not provide the temporal resolution necessary for achieving the highsensitivity needed for validity of the two Pro-Point and Anti-Pointtests. More particularly, using the laser detection system describedabove for stimulus onset and piezo transducer for sensing touch, wefound that the error in iPad capacitive-based touch latencies (i.e.,time between stimulus onset and capacitive touch latency) compared tothe recorded real-world touch latencies was 63.59 ms greater than therecorded real-world touch latency and on average had a calculationvariance of 44. (As used herein, “ms” means millisecond or “msec” andthe terms “ms” and “msec” are used interchangeably). Using the lighttrigger/photodetector system described above for stimulus onset andpiezo transducer for sensing touch on an iPad2, we found that therecorded real-world touch latencies was 72.24 ms greater the recordedreal-world touch latency and on average had a calculation variance of 35Thus we were faced with two problems. The main problem was lack ofaccuracy using the iPad (capacitive-based) touch latencies and thesecondary problem was lack of precision.

For the main problem in using the iPad touchscreen for cognitive testing(lack of touch detection precision because iPad's native mechanism forsensing touch is capacitance based), a mechanism had to be designed toprovide significantly enhanced temporal resolution (variabilityreduction from about 44 or 35 msec to sub millisecond). To improveprecision of the touch, in one embodiment we used the built inmicrophone on the iPad to add information from a recorded audio trace ofthe touch with a sampling rate 44 kHz (sampled every 0.02 ms). In anembodiment, referring to FIG. 3, an internal microphone 7 of the tabletdevice starts recording when the visual stimulus at one of the foursquares 4 a, 4 b, 4 c or 4 d is presented. The tablet device records thetime (“Tv”) the visual stimulus is presented to a target 4 a, 4 b, 4 cor 4 d. Microphone 7 records the sound vibrations caused when a targetsquare is touched (“Tt”). In FIG. 3, the test is Anti-Point, and thetarget square 4 a opposite presented target square 4 c is touched.However, given there was a large unknown delay from the time when acommand to start audio recording is sent to the iPad and the time when afirst audio sample is acquired, it was not clear how to align thecapacitive touch timer with the audio timer.

In order to utilize the information in the audio recording to reduce thelarge variance in the touch (capacitance) latency, we estimated thevariability in the touch latency using the audio trace and then removedit from the capacitive touch latency. In order to solve the problem ofthe audio recording's initial delay, we opened the audio recording onlyonce before the task begins. Second, we calculated the averagedifference between the two timers (i.e., the average difference betweenthe time of the audio signature of touch and the time of the touch fromthe capacitive touch timer) across a set of trials. Third, we adjustedthe touch (capacitance-based) latency on a given trial by adding thevariability of the audio signal on that given trial (i.e., add the timeof the audio signature of touch on that specific trial minus the averagetime of the audio signal calculated in the second step). In this way, wewere able to reduce the variance of the error in estimating the touchlatency from, in this case, 44 ms (touch capacitance signal alone) to0.2 ms (combined touch capacitance and trial specific audio variabilityestimated using the audio trace). Thus with this processing, our testsystem had a temporal resolution for touch of about 0.2 msec. To rejectother noise that may be picked up during the trial, the system lookedfor the distinct signatures in the vicinity of the time reported by theiPad's native touch mechanism.

For the secondary problem (lack of accuracy of the iPad reported touchlatency), the accuracy of the iPad reported touch latency is improved bysubtracting the device delay constant from the capacitive-based latency.This improves the accuracy of the average estimate of latency, but theprecision will remain variable (variance 44 ms). This device delayconstant appears to be consistent and constant for a given hardware,software, and operating system and can be determined in several wayswith tools currently available using an external device as describedabove where we describe the observations that let to the solutions wedescribe.

The primary and secondary corrections of the captured data for accuracyand precision described above is mathematically explained below inreference to FIG. 4.

Nomenclature

The abbreviations on the chart in FIG. 4 have the following meanings:

-   -   Ta Time at which command to start audio recording is sent to        iPad, time also recorded in .log file.    -   Tas Time at which first audio sample is acquired.    -   Ka Constant within a test session, representing the delay        between time recorded in .log file (Ta) and the time when first        sample is collected in audio file (Tas) in msec.    -   Tv Time at which command to draw Target stimulus is sent to        iPad, time also recorded in .log file.    -   Tt Time at which the touch actually occurred.    -   Tc Time at which iPad sends the event that a touch has occurred,        time also recorded in .log file.    -   Dt Variable delay between touch time recorded in .log file (Tc)        and the time when the touch actually occurred (Tt) in msec.        -   Dt=Kc+dt, where Kc is the Mean(Dt) and represents a constant            offset that that will be used to improve accuracy; and where            dt represents the trial-to-trial variation of the capacitive            touch measure that will be used to improve precision.        -   *Note: dt variation is carried through the system. (1) It            determines the variation of Nc (see below). (2) It            determines the variation of the lower and upper bounds,            N_(L) and Nu (see below). (3) Thus, it is the variation of            Wmax (see Equation 5).        -   Kc: Is constant for a particular device and software            configuration.        -   dt: Will be determined by a correction obtained from the            audio recording.    -   Nc sample in audio file corresponding to a time delay of Tc−Ta        from the first audio sample.    -   NL sample in audio file corresponding to an audio window lower        bound, indexed from the first audio sample (Nc−t1).    -   Nu sample in audio file corresponding to an audio window upper        bound, indexed from the first audio sample (Nc+t2).    -   Nmax peak sample in the audio file corresponding to the touch.    -   Tmax Time corresponding to the peak sample.    -   Wmax Time difference between NL and Nmax in msec.

Mean Wmax Average time difference between NL and Nmax across a set oftrials.

Mathematical Treatments

In order to measure the Mean Dt (or Kc) for a particular device, thefollowing procedure is used:

-   -   (1) Measure RT (response time) with iPad (internal measure) and        also externally several times.    -   (2) Conduct a regression between the two measurements.        -   external=iPad*slope+offset. (The external is the gold            standard and it measures the true RTcorrected).        -   Therefore        -   RTcorrected=(Tc−Tv)*slope+offset=(RTcorrected+Dt)*slope+offset=>Dt=[RTcorrected*(1−slope)−offset]/slope.            If slope ˜1, then Dt=−offset.        -   Therefore, the offset estimated with the above regression            with a constraint of unit slope is the Mean Dt (or Kc).

In an iPad experiment without audio or external measurements, only Tcand Tv are available to estimate RT. Thus, as a first approximation:

RTuncorrected=Tc−Tv   (Equation 1)

To improve the accuracy and precision of RT on each trial, we need tosubtract Dt from the above expression. Therefore:

RTcorrected=(Tc−Tv)−Dt   (Equation 2)

Dt varies from trial to trial with Mean(Dt) and Var(Dt) statistics.Therefore

RTcorrected=(Tc−Tv)−(Mean(Dt)+dt)   (Equation 3)

-   -   where dt is the deviation from the mean on a given trial

Mean(Dt) was externally measured, see above. So without audio,subtracting Mean(Dt) improves accuracy of RT but does not improve theprecision of the trial RT. Thus, as a first approximation that correctsfor accuracy only (without audio),

RTpartially_corrected=(Tc−Tv)−Mean(Dt)   (Equation 3b)

To improve precision of RT on each trial, dt on each trial has to beestimated. There is no way to estimate dt for each trial from theinformation gathered in either previous external measurements or in aniPad experiment without audio. In an iPad experiment with audio, Tc, Tvand audio samples (44 kHz sampling rate) whose collection was delayed byKa are available. Ka is a constant delay for a particular experiment(since the audio recording is opened only once at the beginning of theexperiment). Given the high sampling rate and precise audio signature oftouch, it is assumes that any variability in the audio signature oftouch is due to (equal and opposite to) the variability in the precisionof the capacitive touch, dt. Hence:

dt=Dt−Mean(Dt)=Mean(Wmax)−Wmax   (Equation 4)

[Terms are reversed because when Dt is bigger than the Mean(Dt), Wmaxwill be smaller than the Mean(Wmax). This is because the lower bound isvariable and dependent on Dt. Thus, Dt values greater than the mean willresult in Wmax values less than the mean. See the windowing procedurebelow.]

Therefore, Equation 3 becomes:

RTcorrected=(Tc−Tv)−(Mean(Dt)+(Mean(Wmax)−Wmax)).

And simplified:

RTcorrected=Tc−Tv−Mean(Dt)+(Wmax−Mean(Wmax))   (Equation 5)

Thus for equation 5 one must first find Wmax for each trial. To do thisthe following windowing procedure is used.

-   -   (1) Define a window in the audio file to search for the audio        signature of touch, anchored around the sample in the file (Nc)        corresponding to Tc−Ta msec from the first audio sample.        -   (a) Window lower bound (NL): sample corresponding to            Tc−Ta−t1 msec, indexed from the first sample.        -   (b) Window upper bound (Nu): sample in the file            corresponding to Tc−Ta+t2 msec, indexed from the first            sample.    -   (2) Find the sample corresponding to the peak amplitude (audio        signature of touch) within the window (Nmax).        -   (a) Wmax is the time corresponding to the sample from Window            start where the peak (audio signature of touch) occurs            (Nmax).        -   (b) Wmax=Tmax−(Tc−Ta−t1), where (Tc−Ta−t1) represents the            time of the window lower bound, NL

To calculate Mean(Wmax), for all trials in the experiment, find Wmax andaverage it. For each trial, estimate the corrected RT using Equation 5.

The foregoing is explained in reference to process at FIG. 5B. Referringto FIG. 5B, the data from the process of FIG. 5A is analyzed. A programof instructions is started for tablet computer 1 or a computer to whichthe data collected in the process of FIG. 5A is transmitted, and at 122the audio and log files written in the process of FIG. 5A are opened.The program instructs the computer at 124 to read the Tv and Tc data fora trial from the log file; at 126, to calculate Tc−Tv (RTuncorrected);at 128 to define a time window bound (lower bound (NL) to an upper bound(NU)) to search for audio signature of touch in the audio file; at 130to read audio samples from the audio file corresponding to the searchwindow from NL to NU; at 132 to locate the audio sample corresponding tomaximum amplitude (Mmax); at 134 to calculate audio based correctiondt=Wmax−Mean(Wmax) where Mean(Wmax) is an empirically determinedconstant from a set of trials; at 136 to calculate corrected responsetime where RTcorrected=RTuncorrected−Kc+dt, where Kc is an empiricallymeasured constant equal to Mean(Dt); at 138 whether all trials conductedin a set from FIG. 5A are completed is determined, if not, the set iscompleted by instruction to return at 140 to step 124 to read Tv and Tcdata from another trial in the set and re-perform steps 126-138, untilall trials are done, as at 142, at which time, at 144, the computer isinstructed to write the corrected response times for the trials to anoutput. An output could be one or more of a computer file on the device,a summary file written on the screen of the touch screen device, a fileshipped across the network to another computer or storage device, a filewritten to a USB device, a file sent to a print device or another meansof capturing the information.

Thus an embodiment of method and system to determine user reaction timeby correct Tc measured on a portable touch screen device having acapacitive touch-sensitive surface, an acoustic sensor proximal the oneor more modules implemented partially in software, includes, in acomputing device, which may be the same as the portable device oranother computing device having one or more modules implemented at leastpartially in software and to which the data from the portable device istransmitted, comprises 1) opening the audio and log files from step g),2) reading the data from the log file corresponding to Tv and Tc foreach trial, 3) calculating uncorrected response time:RTuncorrected=Tc−Tv for each trial, 4) defining a time window to searchfor audio signatures of touch in the audio file for each trial, 5)reading audio samples from the audio file corresponding to the searchwindow, 6) locating audio samples corresponding to maximum amplitude(Nmax), 7) calculating an audio based correction of dt=Wmax−Mean(Wmax),where Mean(Wmax) is an empirically determined constant from a set oftrials comprising steps a)-f), 8) calculating a corrected response timeRTcorrected=RTuncorrected−Kc+dt, where Kc is an empirically measuredconstant equal to Mean(dt), and 9) writing the corrected response timeto an output. As mentioned above, an output could be one or more of acomputer file on the device, a summary file written on the screen of thetouch screen device, a file shipped across the network to anothercomputer or storage device, a file written to a USB device, a file sentto a print device or another means of capturing the information.

In an embodiment in which accuracy but not precision of a response timeis adequate information, a method and system measures user reactiontimes to visual stimulus on a portable touch screen device having acapacitive touch-sensitive surface with a touch reporting mechanism, andone or more modules at least partially implemented in software, themodules being responsive to a user start command to a) open a time logfile on receipt of the start command; b) generate a visual stimulus at afirst location on the touch screen surface for touch by a user; c)generate a second visual stimulus at a second location on the touchscreen surface spaced from the first location and write time ofgeneration of the second visual stimulus to a log file signifying suchtime of generation (Tv); d) receive notification of capacitance sensedtouch and coordinates of such sensed touch and write timer time to a logfile (Tc) signifying time of such sensed touch and also write the sensedtouch coordinates location to a file; e) remove the second visualstimulus from the touch screen surface, steps b)-f) comprising a singletrial; e) repeat steps b)-e) until a set of trials signified by apredetermined number of capacitance sensed touches (Tc) of the secondlocation attains a preset number, then cease repeating steps b)-e), andclose the log file onto a computer readable medium which may be in thedevice or in communication with the device; and g) in a computingdevice, which may be the same as the portable device or anothercomputing device having one or more modules implemented at leastpartially in software and to which the data from the portable device istransmitted, determine the user reaction time (RT) by 1) opening the logfiles from step f), 2) reading the data from the log file correspondingto Tc for each trial, 3) calculating uncorrected response time:RTuncorrected=Tc−Tv for each trial, 4) calculating response timecorrected for accuracy: RTaccuracy corrected=RTuncorrected−Kc, where Kcis an empirically measured constant corresponding to the average latencyof the capacitive touch reporting mechanism, and 5) writing the accuracycorrected response time to an output.

In one embodiment involving a portable touch screen device having acapacitive touch-sensitive surface and an acoustic sensor proximal thesurface, time of touch of a second visual stimulus located separatelyfrom the first location of visual stimulus generated on the touch screenis not determined by system registration of capacitance and recordationof touch on the second location (Tc) but instead time of touch isdetermined from audio vibrations that occur on touch of the secondlocation. This is essentially the system shown in FIG. 5A without use ofTc, which either can be eliminated or ignored.

This process using only audio vibrations that occur on touch of thesecond location to signify time of touch of the second location (Tt)(determined by the external measurements described above to be less than2 msec from actual or true time of touch) is a process of measuring userreaction times to visual stimulus on a portable touch screen devicehaving a capacitive touch-sensitive surface with a touch reportingmechanism, an acoustic sensor proximal the surface, and one or moremodules implemented partially in software, the modules being responsiveto a user start command to: a) open a time log file on receipt of thestart command; b) generate a visual stimulus at a first location on thetouch screen surface for touch by a user, c) coincident with step b),commence monitoring for input signals from the acoustic sensor and writea timer time to a log file signifying the time start of this monitoring(Ta); d) generate at least one second visual stimulus at a secondlocation on the touch screen surface spaced from the first location andwrite time of generation of the second visual stimulus to a log filesignifying such time of generation (Tv); e) record acoustical vibrationsoriginating from user touch on the touch-sensitive surface at or nearthe second location as sensed by the audio sensor and write a timer timeto a log file signifying initial recording of the sensed vibrations (Tt)originating from the second location and also write coordinates of thesensed touch location to a file; f) remove the second visual stimulusfrom the touch screen surface and stop monitoring the acoustical sensor,steps a)-f) comprising a single trial; g) repeat steps b)-f) until a setof trials signified by a predetermined number of auditory sensor sensedtouches (Tt) of the second location attains a preset number, then ceaserepeating steps b)-f), and close the audio and log files onto a computerreadable medium which may be in the computer or in communication withthe computer; and h) in a computing device, which may be the same as theportable device or another computing device having one or more modulesimplemented at least partially in software and to which the data fromthe portable device is transmitted, determine the user reaction time(RT) by 1) opening the log files from step g), 2) reading the data fromthe log file corresponding to Tv and Tt for each trial, 3) calculatinguncorrected response time: RT=Tt−Tv for each trial, and 4) calculatingresponse time corrected for accuracy: RTaccuracycorrected=RTuncorrected−Kc, where Kc is an empirically measured constantequal to Mean(dt), and 5) writing the accuracy corrected response timeto an output, which could be one or more of a computer file on thedevice, a summary file written on the screen of the touch screen device,a file shipped across the network to another computer or storage device,a file written to a USB device, a file sent to a print device or anothermeans of capturing the information.

In another embodiment, instead of employing the touch screen device towrite the time of presentation of a visual stimulus to a first locationon the screen, an alert is generated at the time of presentation of avisual stimulus to a second location on the screen. The generated alertis detected, input to the device, and the time of such input is writtento a timer log as Tv. All other functions of the foregoing embodimentthat does not make use of Tc are employed. Referring to FIG. 6, a systemand method in which an alert created by the device is detected by anexternal sensor, reported to the device, and the event is written to thetimer log as Tv is shown. Referring to FIG. 6, on a portable touchscreen device having a capacitive touch-sensitive surface with a touchreporting mechanism, an acoustic sensor proximal such surface, an alertsignal generator, an alert signal detector, an audio input port, and oneor more modules at least partially implemented in software, the modulesrespond to a user start command, at 200 to start the program and open alog file, at 202 to start a trial by touching a first location (center)of the touch screen, at 204 to start monitoring audio from the audioport either an internal microphone port or a line input on the device,at 206, to draw the target on the screen and simultaneously produce analert on the device, such as by playing a brief sound buffer on aninternal speaker of the device (a sound trigger) or generating a lighton the screen such as by generating bright lighted pixels on the screen(a light trigger). At 208, the device detects the light trigger using anexternal photodetector and sends a single to the device's line inputport or alternatively to an external vibration device in contact withthe device's touch screen, or if a sound trigger is used, the devicedetects the sound trigger from the internal microphone, at 210 thedevice detects the alert from the monitored audio port and writes atimer time to the log file (Tv) signifying the presentation of thevisual stimulus at the drawn target. At 212, the user touches a target(e.g., either the drawn lighted square in a Pro-Point trial or a squareopposite the lighted square in an Anti-Point trial). At 214 vibrationscreated by the user's touch of the target are picked up by thecomputer's internal microphone port 7 or by using an external microphonethat sends a signal to the device's line input port. At 216 the devicedetects the touch signatures from the monitored audio port, writes atimer time to a log file signifying the time of touch (Tt), and writesthe location coordinates of touch to file. At 218 the device isinstructed to remove the target, and if a light trigger is used, alsothe light trigger, from the screen and stop audio monitoring. At 220, adetermination is made whether a set of a number of error free trials (48in the examples described herein) is completed, and if so, as at 224after “yes,” the log file is closed onto a computer readable mediumwhich may be in the device or in communication with the device, and theprogram of instructions is ended, but if a set of a number of trials isnot completed, as at “no”, the process repeats at 222 to start anothertrial at 202, and the entire process repeats until the full set iscompleted, as at 220 “yes,” at which time, at 224, the log file isclosed onto a computer readable medium which may be in the device or incommunication with the device, and the program of instructions is ended.

In either the sound trigger embodiment or the light trigger embodiment,reaction time of the user is determined by opening the log files from224, reading the data from the log file corresponding to Tv and Tt foreach trial, calculating uncorrected response time: RT=Tt−Tv for eachtrial, and writing the response time to an output.

The process of either the sound trigger embodiment or the light triggerembodiment is more succinctly stated as a method of measuring userreaction times to visual stimulus on a portable touch screen devicehaving a capacitive touch-sensitive surface with a touch reportingmechanism, an acoustic sensor proximal the surface, an alert signalgenerator, an alert signal detector, an audio input port, and one ormore modules at least partially implemented in software, the modulesbeing responsive to a user start command to a) open a time log file onreceipt of the start command; b) coincident with step a), commencemonitoring on the audio input port for input from the alert signaldetector and write a timer time to a log file signifying the time ofstart of this monitoring (Ta); c) generate a visual stimulus at a firstlocation on the touch screen surface for touch by a user; d) generate asecond visual stimulus at a second location on the touch screen surfacespaced from the first location and at the same time activate the alertsignal generator and write time of receipt of a signal from the alertsignal detector to a log file signifying the time of generation of thesecond visual stimulus (Tv); e) detect acoustical vibrations originatingfrom user touch on the touch-sensitive surface at or near the secondlocation as sensed by the acoustic sensor and write a timer time to alog file signifying initial recording of the sensed vibrations (Tt)originating from the second location and also write coordinates of thesensed touch location to a file; f) remove the second visual stimulusfrom the touch screen surface and stop monitoring the audio input port,steps b)-f) comprising a single trial; g) repeat steps b)-f) until a setof trials signified by a predetermined number of auditory sensor sensedtouches (Tt) of the second location attains a preset number, then ceaserepeating steps b)-f), and close the log file onto a computer readablemedium which may be in the device or in communication with the device;h) in a computing device, which may be the same as the portable deviceor another computing device having one or more modules implemented atleast partially in software and to which the data from the portabledevice is transmitted, determining the user reaction time by 1) openingthe log files from step g), 2) reading the data from the log filecorresponding to Tv and Tt for each trial, 3) calculating response time:RT=Tt−Tv for each trial, and d) writing the response time to an output.

FIG. 7 is a chart of audio, visual and touch event and log timer timesof the events in the methods and systems of FIG. 6 and draws on thenomenclature set forth above.

Summarizing, we developed a method and system using a tablet basedportable system with special signaling techniques precise enough fortesting to detect mild cognitive changes (deficits/improvements). Anindividual self-administers two tests on a tablet device (e.g. an AppleiPad). In one test (the Pro-Point test), the individual responds to avisual stimulus on the tablet's screen by lifting his/her finger from afixed center location and touching the location where the stimulusappeared as soon as possible. In the second test (the Anti-Point test),the individual responds to a visual stimulus on the tablet's screen bylifting his/her finger from a fixed center location and touching thelocation opposite to where the stimulus appeared. In both tests, thetime the visual stimulus is presented and the time it takes to touch theappropriate location are recorded. In one embodiment, the times arerecorded from the touch screen as well as the tablet's microphonesystem. Temporal accuracy and precision of pointing are corrected fromthese recorded coordinates. Also recorded are the coordinates of thelocation that was touched. In other embodiments, time of touch does notuse the touch screens recognition and recording of time of touch,although the coordinates of the location that was touched as sensed bythe touch screen are recorded. The time and spatial recordings arecalibrated and reported with high temporal precision and spatialprecision. The calculations and analysis can be performed by a programrun in the tablet computer or the recorded data can be transmitted to aseparate computer for that purpose and for storage and further analysisas desired. Everything that is needed to test an individual and analyzethe data or to transfer the recorded data to an additional computerusing network functionality built into the system for further analysisand storage is built into the system.

Because the embodiments as disclosed herein are tablet based, they areportable, cheap and accessible to virtually anyone in the world. Theembodiments are simple and intuitive to use and requires minimalmaintenance. The embodiments provide objective measurements of cognitivefunction, are minimally dependent on language, and require only thatsubjects can point. The embodiments are thus applicable across a verybroad age range from young children to seniors. The two pointing testsprobe specific brain functions with very high sensitivity. The Pro-Pointtest probes automatic brain functions whereas the Anti-Point test probescognitive or willful brain functions. The Pro-Point test also serves asa control for basic sensory motor and general alertness functions.

It is important to note that over the years there are many variants ofeye movement tasks, such as a delayed remembered antisaccade, that canbe implemented by use of our methods and systems as well to obtainmeasures of cognitive control and memory. While the Pro-Point andAnti-Point tests are exemplified as a means of measuring stimulusresponse, other different or additional visual tasks or stimuli could bepresented in many different fashions, but ultimately, one would still bemeasuring response time in accordance with our invention. As anon-limiting example, in a variation of our Pro-Touch and Anti-Touchtests, we developed other simple tasks, for example tasks of reflexiveand voluntary social attention that momentarily flash a figure of a headwith eyes pointing left or right while the center dot is touched beforethe second visual stimulus is presented to a target location butotherwise using the same methods and systems measuring response times.

Tests of Device to Detect Mild Concussion From Heading by Young SoccerPlayers

In this example, embodiments of the invention were successfully used todetect mild cognitive deficits in soccer players after ball heading. Inthis study the accuracy and speed of automatic (using Pro-Point test)and willful pointing (using Anti-point test) were compared in two groupsof high-school subjects: Soccer players and Non-soccer players. Thetesting was performed on the soccer field demonstrating the portabilityand field applicability of the system. Further, the testing wasperformed by a high-school student with supervision, which demonstratesthe simplicity of the system. It was found that the accuracy in bothtypes of pointing responses was identical in the two groups. Inaddition, the speed of automatic pointing was also identical in the twogroups. However, the speed of willful pointing differed significantly inthe two groups: soccer players were slower than non-soccer players.Further, it was found that the speed of willful responses marginallydepended on the number of ball headings and significantly depended onhours of soccer played per week and years of experience. Together, theseresults confirm the ability of the system to detect subtle butsignificant changes in cognitive functions in humans.

Studies on Concussion From Heading in Soccer Players Prior to Ours DidNot Detect Mild Concussions

Concussive brain injuries in head jarring sports such as Americanfootball, hockey, and boxing, where repeated loss of consciousness oftenoccur, could lead to long-term cognitive dysfunctions1. However, whetherless violent head impacts such as heading a soccer ball could lead tosubconcussive brain injury is unclear 2-4. A recent imaging study5showed detectable structural differences in brain areas, consistent withtraumatic brain injury (TBI), between amateur adult (mean age of 31yrs., played soccer since childhood) soccer players with self-reportedhigh and low heading frequencies. Similar findings were also obtained inanother recent imaging study 6 which found differences in white matterintegrity in a small sample of professional male soccer players (meanage of 20 yrs., who played soccer since childhood) compared with acontrol group of swimmers (mean age of 21 yrs.). Previous imagingstudies have failed to find structural brain differences directlyrelated to heading balls 7-10. Previous studies using formal cognitivetesting have also failed to detect changes with ball heading in youngadults 11 or in 13- to 16-year-old soccer players.

Frontal lobes are among the brain regions most susceptible to injury intraumatic brain injury15. Previous studies that did not find significantchanges in higher level cognitive tasks associated with soccer ballheading 10,11 have often tested for cognitive changes using more formalbut complicated cognitive testing (e.g., visual memory retention,addition, logic, and other tasks that occur at the level of seconds andminutes). We used the new touch based method described above, with taskssimilar to those used in eye tracking research, which are simple,straightforward, and less sensitive to interfering issues such as secondlanguage differences system, to test to detect the cognitive effects ofsoccer ball heading by a small sample of young girls of high school age.Our method with its relatively short response latencies and hightemporal resolution may be a more sensitive test of executive functionand hence be able to detect more subtle cognitive changes in high schoolsoccer players, deficits that were previously undetected because of lackof sensitive measurement techniques.

Methods

The participants were 12 female soccer and 12 female non-soccer playersin a high school (median age for both groups=16.5 years; range for bothgroups was 15-18 years). Both soccer and non-soccer players wererecruited through the high school, and a research assistant explainedthe study to them. The high school was supportive of the study butwanted to minimize any inconvenience to the students, their parents (forminors under 18), and their sports schedule. The soccer sessions wereactual varsity training sessions that were on their own tight scheduleand it was not possible to run a pre-practice control. The varsity coachcontrolled the practice, including the heading portion, and we did nothave control over what soccer related activity the players performed.

All participants gave informed consent or assent with parental consentand the study was approved by the University of Texas at HoustonCommittee for the Protection of Human Subjects in accordance with theDeclaration of Helsinki. In addition, the study was also approved by theadministration of the high school as well as the coaches. Every soccerplayer performed head balls during the practice session before thetesting, with median 6 (range: 2-20) head bails per session based onself-reports. Data for two of the soccer subjects were not included inthe descriptive statistics of heading ball rate or used for the analysisof this variable as their answers were qualitative. No participant inthe non-soccer group performed a head ball before testing. The medians(and ranges) for years of soccer playing and current weekly hours ofsoccer playing were respectively 8 years (range: 5-12) and 11 hours(range: 2-16), for soccer players and 0 and 0 for non-soccer players.The non-soccer players were recruited similar to soccer players with theadditional inclusion criteria that they were not currently active in acontact sport and that their age and grade level was matched to thesoccer players. All participants had normal or corrected-to-normalvision and none reported any previous head injury nor any other knownneurological conditions. The medians for the numbers of hours of video(electronic) game playing were 4.0 and 2.5 hours for soccer andnon-soccer players. Eleven of the twelve participants in both the soccerand non-soccer groups were right handed.

Stimuli. The experiment was performed on an iPad 2 (FIG. 1) with a videoframe refresh rate of 60 Hz. The onset and offset of stimuli weresynchronized with the frame refresh signal with a precision of 1.6 msec23. The visual display consisted of a filled center fixation circle(diameter subtending 2.4° visual angle from a 33 cm viewing distance,1.4 cm) surrounded by four square boxes (1.4°, 0.8 cm) 7.0° (4.0 cm)from the fixation circle indicating possible response locations.Participants started a trial by placing their index finger on the centercircle. A visual target (white square, 0.8 cm) appeared randomly 480 mslater, at one of the four locations. For the Pro-Point task, theparticipant was instructed to touch the response box containing thetarget as fast as possible without making errors. For the Anti-Pointtask, the participant was to touch the response box opposite to thetarget location.

Touch responses. The spatial locations of the touches were captured bythe iPad's capacitive touch screen and exact coordinates calculatedusing its touch-screen interface with resolution of 52 pixels per cm. Aresponse was counted as an error if the distance between the targetlocation and the iPad-calculated location was greater than 3.3° (1.9cm). As described above, the touch screen alone cannot be used for hightemporal resolution measurements because of the inherent delayassociated with sensing touch via a capacitive screen as well as thefact that these events are then discretized to the frame refresh rate of60 Hz. A temporal resolution of 0.2 msec can be achieved by using thebuilt-in microphone (44.1 kHz sampling rate) on the iPad to record thevibrations produced by touch onset and offset 23.

Design and Procedure. The dependent variables were: (1) InitiationTime—the duration between when the visual cue appears and when thefinger is lifted, (2) Movement Time—the duration between when the visualcue appears and when the target goal (at the cue or opposite of the cuelocation) is touched, (3) Total Time—sum of Initiation Time and MovementTime, and (4) Error—when the finger touched more than 3.3° (1.9 cm) fromthe target goal center. Each participant performed two blocks of trialsuntil they obtained 48 correct trials in each Pro-Point and Anti-Pointblock (mean total trials 48.3 and 49.4, respectively). Within eachparticipant group, half started with the Pro-Point block followed by theAnti-Point block, and the other half received the reversed order. Bothgroups were tested after school academic activities were over. Soccerplayers went to practice right after school academic activities and thenwere tested in the field immediately following their afternoon practice.To match the environmental conditions, Non-soccer players were alsotested outdoors after school academic activities were over atapproximately the same time in the afternoon (4-5 pm).

Analysis. Error trials were excluded from the analyses of responsetimes. Outlier trials with times more than 2.5 SD away from the mean ofeach subject for each task were excluded iteratively until all remainingtrials were within 2.5 SD, removing, for initiation times, 6.86%(Pro-Point) and 3.91% (Anti-Point) and, for movement times, anadditional 0.95% and 2.60% of the total trials, respectively. A mixedeffect model was performed for response time data and a logit-linkgeneralized linear model with repeated measurements for error data. Thelogit-link transforms error percentage, p, to logit(p) by log[p/(1−p)].All models assumed that measurements obtained within each subject havean autoregressive correlation structure, AR(1). Group (soccer vs.non-soccer players) was the between-subject variable for each task(Pro-Point and Anti-Point) and group difference was calculated andtested by constructing the contrasts from the mixed effect models orlogit-link generalized linear model. In addition, to test if theAnti-Point response time slowing in the soccer group found in the firstgroup analysis was related to ball heading, years of soccer, or currentweekly hours of soccer playing, we performed a similar mixed effectmodel (with repeated measurements and autoregressive correlationstructure) on the Anti-Point response time data from the soccer playerswith the independent variables of heading rate (n=10), years of soccerplaying (n=12), and hours of soccer per week (n=12). Due to missingdata, analyses were run separately. Data were analyzed using asignificance level of p<0.05 and a marginal significance level of0.05≤p<0.10.

Results

FIG. 8 shows estimated mean initiation, movement, and total reactiontimes for soccer and non-soccer subjects Darker bars represent data fromsoccer players, and lighter bars represent data from non-soccer players.Error bars indicate the 95% confidence interval (d.f.=11). Note that thescale for total time (far right) is different from that of theinitiation and movement times. Significance levels: (t) for p<0.1, (*)for p<0.01, and (**) for p<0.005 14 illustrates mean initiation,movement, and total times to respond to the target as a function of taskfor both groups. In Pro-Point, there were no differences between soccerand non-soccer players for initiation times (312 ms vs. 313 ms,t(22)=0.16, p=0.87), movement times (445 ms vs. 439 ms, t(22)=1.18,p=0.25), or total times (757 ms vs. 752 ms, t(22)=0.55, p=0.59) usingthe mixed effect model. In contrast, in Anti-Point, soccer players weremarginally slower than non-soccer players for initiation times (394 msvs. 378 ms, t(22)=1.86, p=0.08) and significantly slower than non-soccerplayers for movement times (561 ms vs. 531 ms, t(22)=3.69, p<0.005) andtotal times (955 ms vs. 909 ms, t(22)=2.81, p=0.01) using the mixedeffect model.

To further test if Anti-Point response times in soccer players could beaccounted for by heading frequency or soccer experience, we includedthese three variables as independent variables. The mixed effect modelwith heading ball rate as the independent variable showed marginaleffects of heading ball rate for initiation time (t(8)=1.88, p<0.10) andtotal time (t(8)=1.86, p<0.10), but not movement time (t(8)=1.67,p>0.11) in the Anti-Point task, indicating marginally slower responseswith increased number of head balls. With hours of soccer per week asthe independent variable, the mixed effect model showed significanteffects for Anti-Point task initiation time (t(10)=3.51, p<0.01),movement time (t(10)=2.27, p<0.05) and total time (t(10)=2.95, p<0.02),indicating slower responses with increased hours of soccer per week.Thirdly, with years of soccer as the independent variable, the mixedeffect model showed a marginal effect for Anti-Point task initiationtime (t(10)=2.94, p<0.07) and significant effects for movement time(t(10)=3.43, p<0.01) as well as total time (t(10)=2.71, p<0.03),indicating slower responses with increased years of soccer experience.Finally, it was determined that the independent variables of headingball rate, hours of soccer played per week, and years of soccer playedwere unrelated/uncorrelated by Pearson correlation coefficients.

There were no significant differences in errors in either Pro-Pointtasks (0.3% vs. 1.0%, z=0.83, p=0.41, logit-link generalized model) orAnti-Point (3.1% vs. 2.5%, z=1.13, p=0.26, for soccer and non-soccerplayers, logit-link generalized model).

Conclusion of Tests Using Embodiment

The results show that soccer playing in which participants headed theball did indeed disrupt voluntary performance in female high schoolsoccer players tested immediately following practice. In addition, evenin this small sample, this response time slowing on the Anti-Point taskwas marginally related to number of ball headers (n=10) andsignificantly related to hours of soccer per week (n=12) and years ofsoccer playing (n=12). We found no evidence that slowing occurred duringreflexive movements under identical sensorimotor conditions (Pro-Point).These findings demonstrate significant and specific cognitive changes infemale high school soccer players who head the soccer ball duringpractice.

Though the changes we report were robust, they do not necessarily implysustained changes or brain injury. To our knowledge, these resultsprovide the first evidence that even subconcussive blows in soccer couldlead to measureable, even if possibly transient, cognitive changes inyoung soccer players.

In sum, the cognitive changes that we report were measured with anembodiment comprising a simple iPad based application. A simple toolsuch as this embodiment involving an iPad application may be a quick andeffective method to screen for and track cognitive deficits in sportsplayers. It could potentially be used to detect, screen, and track otherpopulations for mild traumatic brain injury and development of cognitivecomorbidities.

The tests are very simple and are minimally sensitive to language andage requirements. The system does not require a special or controlledenvironment, training for administration, or scoring by trainedpersonnel or specialist. Further, the tablet platform on which the testsrun is extremely simple to use and maintain. Everything that is neededto test an individual and to transfer the recorded data to an additionalcomputer is built into the device.

In the foregoing specification, the invention has been described withreference to specific embodiments. However, one of ordinary skill in theart appreciates that various modifications and changes can be madewithout departing from the scope of the invention. Accordingly, thespecification and figures are to be regarded in an illustrative ratherthan a restrictive sense, and all such modifications are intended to beincluded within the scope of invention.

Although the invention has been described with respect to specificembodiments thereof, these embodiments are merely illustrative, and notrestrictive of the invention. The description herein of illustratedembodiments of the invention is not intended to be exhaustive or tolimit the invention to the precise forms disclosed herein (and inparticular, the inclusion of any particular embodiment, feature orfunction is not intended to limit the scope of the invention to suchembodiment, feature or function). Rather, the description is intended todescribe illustrative embodiments, features and functions in order toprovide a person of ordinary skill in the art context to understand theinvention without limiting the invention to any particularly describedembodiment, feature or function. While specific embodiments of, andexamples for, the invention are described herein for illustrativepurposes only, various equivalent modifications are possible within thespirit and scope of the invention, as those skilled in the relevant artwill recognize and appreciate. As indicated, these modifications may bemade to the invention in light of the foregoing description ofillustrated embodiments of the invention and are to be included withinthe spirit and scope of the invention. Thus, while the invention hasbeen described herein with reference to particular embodiments thereof,a latitude of modification, various changes and substitutions areintended in the foregoing disclosures, and it will be appreciated thatin some instances some features of embodiments of the invention will beemployed without a corresponding use of other features without departingfrom the scope and spirit of the invention as set forth. Therefore, manymodifications may be made to adapt a particular situation or material tothe essential scope and spirit of the invention.

Reference throughout this specification to “one embodiment,” “anembodiment,” or “a specific embodiment” or similar terminology meansthat a particular feature, structure, or characteristic described inconnection with the embodiment is included in at least one embodimentand may not necessarily be present in all embodiments. Thus, respectiveappearances of the phrases “in one embodiment,” “in an embodiment,” or“in a specific embodiment” or similar terminology in various placesthroughout this specification are not necessarily referring to the sameembodiment. Furthermore, the particular features, structures, orcharacteristics of any particular embodiment may be combined in anysuitable manner with one or more other embodiments. It is to beunderstood that other variations and modifications of the embodimentsdescribed and illustrated herein are possible in light of the teachingsherein and are to be considered as part of the spirit and scope of theinvention.

In the description herein, numerous specific details are provided, suchas examples of components and/or methods, to provide a thoroughunderstanding of embodiments of the invention. One skilled in therelevant art will recognize, however, that an embodiment may be able tobe practiced without one or more of the specific details, or with otherapparatus, systems, assemblies, methods, components, materials, parts,and/or the like. In other instances, well-known structures, components,systems, materials, or operations are not specifically shown ordescribed in detail to avoid obscuring aspects of embodiments of theinvention. While the invention may be illustrated by using a particularembodiment, this is not and does not limit the invention to anyparticular embodiment and a person of ordinary skill in the art willrecognize that additional embodiments are readily understandable and area part of this invention.

Any suitable programming language can be used to implement the routines,methods or programs of embodiments of the invention described herein,including C, C++, Java, assembly language, etc. Different programmingtechniques can be employed such as procedural or object oriented. Anyparticular routine can execute on a single computer-processing device ormultiple computer processing devices, a single computer processor ormultiple computer processors. Data may be stored in a single storagemedium or distributed through multiple storage mediums, and may residein a single database or multiple databases (or other data storagetechniques). Although the steps, operations, or computations may bepresented in a specific order, this order may be changed in differentembodiments. In some embodiments, to the extent multiple steps are shownas sequential in this specification, some combination of such steps inalternative embodiments may be performed at the same time. The sequenceof operations described herein can be interrupted, suspended, orotherwise controlled by another process, such as an operating system,kernel, etc. The routines can operate in an operating system environmentor as stand-alone routines. Functions, routines, methods, steps andoperations described herein can be performed in hardware, software,firmware or any combination thereof.

Embodiments described herein can be implemented in the form of controllogic in software or hardware or a combination of both. The controllogic may be stored in an information storage medium, such as acomputer-readable medium, as a plurality of instructions adapted todirect an information-processing device to perform a set of stepsdisclosed in the various embodiments. Based on the disclosure andteachings provided herein, a person of ordinary skill in the art willappreciate other ways and/or methods to implement the invention.

It is also within the spirit and scope of the invention to implement insoftware programming or of the steps, operations, methods, routines orportions thereof described herein, where such software programming orcode can be stored in a computer-readable medium and can be operated onby a processor to permit a computer to perform any of the steps,operations, methods, routines or portions thereof described herein. Theinvention may be implemented by using software programming or code inone or more general purpose digital computers, by using applicationspecific integrated circuits, programmable logic devices, fieldprogrammable gate arrays, optical, chemical, biological, quantum ornanoengineered systems, components and mechanisms may be used. Ingeneral, the functions of the invention can be achieved by any means asis known in the art. For example, distributed, or networked systems,components and circuits can be used. In another example, communicationor transfer (or otherwise moving from one place to another) of data maybe wired, wireless, or by any other means.

It will also be appreciated that one or more of the elements depicted inthe drawings/figures can also be implemented in a more separated orintegrated manner, or even removed or rendered as inoperable in certaincases, as is useful in accordance with a particular application.Additionally, any signal arrows in the drawings/figures should beconsidered only as exemplary, and not limiting, unless otherwisespecifically noted.

Benefits, other advantages, and solutions to problems have beendescribed above with regard to specific embodiments. However, thebenefits, advantages, solutions to problems, and any component(s) thatmay cause any benefit, advantage, or solution to occur or become morepronounced are not to be construed as a critical, required, or essentialfeature or component.

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33-34. (canceled)
 35. A method of measuring user reaction times to avisual stimulus on a portable touch screen device having a capacitivetouch-sensitive surface with a touch reporting mechanism, an acousticsensor proximal said surface, an alert signal generator, an alert signaldetector, an audio input port, and one or more modules at leastpartially implemented in software, said one or more modules beingresponsive to a user start command to a) open a time log file on receiptof the start command, b) coincident with step a), commence monitoring onsaid audio input port for input from said alert signal detector andwrite a timer time to the log file signifying the time of start of thismonitoring (Ta), c) generate a visual stimulus at a first location onthe touch screen surface for touch by a user, d) generate at least onesecond visual stimulus at a second location on the touch screen surfacespaced from said first location and at the same time activate said alertsignal generator and write time of receipt of a signal from said alertsignal detector to the log file signifying the time of generation ofsaid second visual stimulus (Tv), e) detect acoustical vibrationsoriginating from user touch on said touch-sensitive surface at or nearsaid second location as sensed by said acoustic sensor and write a timertime to the log file signifying initial recording of said sensedvibrations (Tt) originating from said second location and also writecoordinates of the sensed touch location to a file, f) remove the secondvisual stimulus from the touch screen surface and stop monitoring theaudio input port, steps b)-f) comprising a single trial, g) repeat stepsb)-f) until a set of trials signified by a predetermined number ofauditory sensor sensed touches (Tt) of said second location attains apreset number, then cease repeating steps b)-f), and close the log fileonto a computer readable medium which may be in said device or incommunication with said device, and h) in a computing device which maybe the same as said portable device or another computing device havingone or more modules implemented at least partially in software and towhich the data from said portable device is transmitted, determining auser reaction time (RT) by 1) opening the log file from step g), 2)reading the data from the log file corresponding to Tv and Tt for eachtrial, 3) calculating an accurate and precise response time: RT=Tt−Tvfor each trial, and 4) writing the corrected response time to an output.36. The method of claim 35 in which said step c) further comprisesgenerating a first fixed location and a plurality of additional fixedsecond locations equally radially spaced from the first location on saidtouch sensitive surface, at least one such additional second locationbeing opposite another such additional second location and anyadditional second locations being equally circumferentially spaced froma next circumferentially adjacent additional second location, and saidstep d) further comprises generating a second visual stimulus on one ofsaid additional second locations on the touch sensitive surface.
 37. Themethod of claim 35 in which said alert signal generator is an audiogenerator.
 38. The method of claim 37 in which said audio generator isan internal speaker in said device.
 39. The method of claim 37 in whichsaid audio generator is an external vibration device in contact with thedevice's touch screen.
 40. The method of claim 35 in which said alertsignal detector is said acoustic sensor in said device.
 41. The methodof claim 35 in which said alert signal detector is an external acousticsensor connected to the internal line input of the said device.
 42. Themethod of claim 35 in which said alert signal generator comprises pixeldrivers in said touch screen, said alert signal is bright lighted pixelson the screen, said alert signal detector is a photodiode proximal saidtouch screen and wherein a signal from said photodiode is sent to aninternal line input of said device.
 43. The method of claim 35 in whichsaid alert signal generator comprises pixel drivers in said touchscreen, said alert signal is bright lighted pixels on the screen, saidalert signal detector is a photodiode proximal said touch screen andwherein a signal from said photodiode is sent to an external vibrationdevice in contact with the device's touch screen. 44-45. (canceled) 46.A system of measuring user reaction times to a visual stimulus on aportable touch screen device having a capacitive touch-sensitive surfacewith a touch reporting mechanism, an acoustic sensor proximal saidsurface, an alert signal generator, an alert signal detector, an audioinput port, and one or more modules at least partially implemented insoftware, said one or more modules being responsive to a user startcommand to a) open a time log file on receipt of the start command, b)coincident with step a), commence monitoring on said audio input portfor input from said alert signal detector and write a timer time to thelog file signifying the time of start of this monitoring (Ta), c)generate a visual stimulus at a first location on the touch screensurface for touch by a user, d) generate at least one second visualstimulus at a second location on the touch screen surface spaced fromsaid first location and at the same time activate said alert signalgenerator and write time of receipt of a signal from said alert signaldetector to the log file signifying the time of generation of saidsecond visual stimulus (Tv), e) detect acoustical vibrations originatingfrom user touch on said touch-sensitive surface at or near said secondlocation as sensed by said acoustic sensor and write a timer time to thelog file signifying initial recording of said sensed vibrations (Tt)originating from said second location and also write coordinates of thesensed touch location to a file, f) remove the second visual stimulusfrom the touch screen surface and stop monitoring the audio input port,steps b)-f) comprising a single trial, g) repeat steps b)-f) until a setof trials signified by a predetermined number of auditory sensor sensedtouches (Tt) of said second location attains a preset number, then ceaserepeating steps b)-f), and close the log file onto a computer readablemedium which may be in said device or in communication with said device,and h) in a computing device which may be the same as said portabledevice or another computing device having one or more modulesimplemented at least partially in software and to which the data fromsaid portable device is transmitted, determining a user reaction time(RT) by 1) opening the log file from step g), 2) reading the data fromthe log file corresponding to Tv and Tt for each trial, 3) calculatingan accurate and precise response time: RT=Tt−Tv for each trial, and 4)writing the corrected response time to an output.
 47. The system ofclaim 46 in which said step c) further comprises generating a firstfixed location and a plurality of additional fixed second locationsequally radially spaced from the first location on said touch sensitivesurface, at least one such additional second location being oppositeanother such additional second location and any additional secondlocations being equally circumferentially spaced from a nextcircumferentially adjacent additional second location, and said step d)further comprises generating a second visual stimulus on one of saidadditional second locations on the touch sensitive surface.
 48. Thesystem of claim 46 in which said alert signal generator is an audiogenerator.
 49. The system of claim 48 in which said audio generator isan internal speaker in said device.
 50. The system of claim 48 in whichsaid audio generator is an external vibration device in contact with thedevice's touch screen.
 51. The system of claim 46 in which said alertsignal detector is said acoustic sensor in said device.
 52. The systemof claim 46 in which said alert signal detector is an external acousticsensor connected to the internal line input of the said device.
 53. Thesystem of claim 46 in which said alert signal generator comprises pixeldrivers in said touch screen, said alert signal is bright lighted pixelson the screen, said alert signal detector is a photodiode proximal saidtouch screen and wherein a signal from said photodiode is sent to aninternal line input of said device.
 54. The system of claim 46 in whichsaid alert signal generator comprises pixel drivers in said touchscreen, said alert signal is bright lighted pixels on the screen, saidalert signal detector is a photodiode proximal said touch screen andwherein a signal from said photodiode is sent to an external vibrationdevice in contact with the device's touch screen.